Clean up the CRC-10 code.

Have the wsutil routine just accumulate the stuff from the buffer handed
to us.  Have the IUUP dissector deal with the extra stuff.  Add a
update_crc10_by_bytes_tvb() routine, which is passed a tvbuff, offset,
and length, and use that rather than using tvb_get_ptr() in dissectors.

Change-Id: Iadd0823c764080e60d1339abb94d2e19150eabfe
Reviewed-on: https://code.wireshark.org/review/3509
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 3 insertions, 63 deletions

diff --git a/epan/dissectors/packet-atm.c b/epan/dissectors/packet-atm.c
index 96e4b8674b..c8cec768bc 100644
--- a/epan/dissectors/packet-atm.c
+++ b/epan/dissectors/packet-atm.c
@@ -29,6 +29,7 @@
 #include <epan/addr_resolv.h>
 #include <epan/ppptypes.h>
 #include <epan/expert.h>
+#include <epan/crc10-tvb.h>
 
 #include "packet-atm.h"
 #include "packet-snmp.h"
@@ -1476,65 +1477,6 @@ const value_string atm_pt_vals[] = {
   { 0, NULL }
 };
 
-/*
- * Charles Michael Heard's CRC-10 code, from
- *
- *      http://web.archive.org/web/20061005231950/http://cell-relay.indiana.edu/cell-relay/publications/software/CRC/crc10.html
- *
- * with the CRC table initialized with values computed by
- * his "gen_byte_crc10_table()" routine, rather than by calling that
- * routine at run time, and with various data type cleanups.
- */
-static const guint16 byte_crc10_table[256] = {
-  0x0000, 0x0233, 0x0255, 0x0066, 0x0299, 0x00aa, 0x00cc, 0x02ff,
-  0x0301, 0x0132, 0x0154, 0x0367, 0x0198, 0x03ab, 0x03cd, 0x01fe,
-  0x0031, 0x0202, 0x0264, 0x0057, 0x02a8, 0x009b, 0x00fd, 0x02ce,
-  0x0330, 0x0103, 0x0165, 0x0356, 0x01a9, 0x039a, 0x03fc, 0x01cf,
-  0x0062, 0x0251, 0x0237, 0x0004, 0x02fb, 0x00c8, 0x00ae, 0x029d,
-  0x0363, 0x0150, 0x0136, 0x0305, 0x01fa, 0x03c9, 0x03af, 0x019c,
-  0x0053, 0x0260, 0x0206, 0x0035, 0x02ca, 0x00f9, 0x009f, 0x02ac,
-  0x0352, 0x0161, 0x0107, 0x0334, 0x01cb, 0x03f8, 0x039e, 0x01ad,
-  0x00c4, 0x02f7, 0x0291, 0x00a2, 0x025d, 0x006e, 0x0008, 0x023b,
-  0x03c5, 0x01f6, 0x0190, 0x03a3, 0x015c, 0x036f, 0x0309, 0x013a,
-  0x00f5, 0x02c6, 0x02a0, 0x0093, 0x026c, 0x005f, 0x0039, 0x020a,
-  0x03f4, 0x01c7, 0x01a1, 0x0392, 0x016d, 0x035e, 0x0338, 0x010b,
-  0x00a6, 0x0295, 0x02f3, 0x00c0, 0x023f, 0x000c, 0x006a, 0x0259,
-  0x03a7, 0x0194, 0x01f2, 0x03c1, 0x013e, 0x030d, 0x036b, 0x0158,
-  0x0097, 0x02a4, 0x02c2, 0x00f1, 0x020e, 0x003d, 0x005b, 0x0268,
-  0x0396, 0x01a5, 0x01c3, 0x03f0, 0x010f, 0x033c, 0x035a, 0x0169,
-  0x0188, 0x03bb, 0x03dd, 0x01ee, 0x0311, 0x0122, 0x0144, 0x0377,
-  0x0289, 0x00ba, 0x00dc, 0x02ef, 0x0010, 0x0223, 0x0245, 0x0076,
-  0x01b9, 0x038a, 0x03ec, 0x01df, 0x0320, 0x0113, 0x0175, 0x0346,
-  0x02b8, 0x008b, 0x00ed, 0x02de, 0x0021, 0x0212, 0x0274, 0x0047,
-  0x01ea, 0x03d9, 0x03bf, 0x018c, 0x0373, 0x0140, 0x0126, 0x0315,
-  0x02eb, 0x00d8, 0x00be, 0x028d, 0x0072, 0x0241, 0x0227, 0x0014,
-  0x01db, 0x03e8, 0x038e, 0x01bd, 0x0342, 0x0171, 0x0117, 0x0324,
-  0x02da, 0x00e9, 0x008f, 0x02bc, 0x0043, 0x0270, 0x0216, 0x0025,
-  0x014c, 0x037f, 0x0319, 0x012a, 0x03d5, 0x01e6, 0x0180, 0x03b3,
-  0x024d, 0x007e, 0x0018, 0x022b, 0x00d4, 0x02e7, 0x0281, 0x00b2,
-  0x017d, 0x034e, 0x0328, 0x011b, 0x03e4, 0x01d7, 0x01b1, 0x0382,
-  0x027c, 0x004f, 0x0029, 0x021a, 0x00e5, 0x02d6, 0x02b0, 0x0083,
-  0x012e, 0x031d, 0x037b, 0x0148, 0x03b7, 0x0184, 0x01e2, 0x03d1,
-  0x022f, 0x001c, 0x007a, 0x0249, 0x00b6, 0x0285, 0x02e3, 0x00d0,
-  0x011f, 0x032c, 0x034a, 0x0179, 0x0386, 0x01b5, 0x01d3, 0x03e0,
-  0x021e, 0x002d, 0x004b, 0x0278, 0x0087, 0x02b4, 0x02d2, 0x00e1,
-};
-
-/* update the data block's CRC-10 remainder one byte at a time */
-static guint16
-update_crc10_by_bytes(guint16 crc10_accum, const guint8 *data_blk_ptr,
-                      int data_blk_size)
-{
-  register int i;
-
-  for (i = 0;  i < data_blk_size; i++) {
-    crc10_accum = ((crc10_accum << 8) & 0x3ff)
-      ^ byte_crc10_table[( crc10_accum >> 2) & 0xff]
-      ^ *data_blk_ptr++;
-  }
-  return crc10_accum;
-}
-
 static const value_string st_vals[] = {
   { 2, "BOM" },
   { 0, "COM" },
@@ -1743,8 +1685,7 @@ dissect_atm_cell(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
     proto_tree_add_item(aal_tree, hf_atm_aal3_4_multiplex_id, tvb, offset, 2, ENC_BIG_ENDIAN);
 
     length = tvb_length_remaining(tvb, offset);
-    crc10 = update_crc10_by_bytes(0, tvb_get_ptr(tvb, offset, length),
-                                  length);
+    crc10 = update_crc10_by_bytes_tvb(0, tvb, offset, length);
     offset += 2;
 
     proto_tree_add_item(aal_tree, hf_atm_aal3_4_information, tvb, offset, 44, ENC_NA);
@@ -1790,8 +1731,7 @@ dissect_atm_cell(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
       break;
     }
     length = tvb_length_remaining(tvb, offset);
-    crc10 = update_crc10_by_bytes(0, tvb_get_ptr(tvb, offset, length),
-                                  length);
+    crc10 = update_crc10_by_bytes_tvb(0, tvb, offset, length);
     offset += 1;
 
     proto_tree_add_item(aal_tree, hf_atm_aal_oamcell_func_spec, tvb, offset, 45, ENC_NA);